<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
    <title>弹窗操作</title>
</head>
    <body>
        <input type="button" id="alert" value="alert弹窗" onclick="alert('这是alert()弹窗!')">
        <input type="button" id="confirm"value="confirm弹窗" onclick="confirm('这是confirm()弹窗！')" >
        <input type="button" id="prompt" value="prompt弹窗" onclick="prompt('这是prompt()弹窗！','这是prompt()弹窗的默认值！')">
    </body>
</html>